About 45 minutes into Whitechapel (ITV1), the first and so far only suspect appeared, screaming that he was photophobic. It was sod's law, I suppose, that he turned up in the only scene shot in something approaching normal daylight. Someone on the set was taking noir rather too literally. The darkness was probably intended to be gothic, but it was annoying, as for long periods I struggled to work out what was going on. Even the police station seemed to be lit by a single five-watt bulb. Great for energy saving, but not for the viewer.

After a rocky second series in which the Kray twins were cloned, Whitechapel has gone back to its 19th-century roots with a recreation of the Ratcliff Highway mUurders. (No, me neither, but apparently a draper and his family were murdered in the East End in 1811 after a servant girl was sent out to buy oysters.) This time round a trendy tailor and his team were offed, while the stroppy assistant, Georgie, nipped out to get some bagels and it was once again thanks to the insight of Ripperologist Edward Buchan (Steve Pemberton) that the connection between past and present was made.

Whitechapel falls into the hinterland of television that isn't quite bad enough to switch off, nor good enough to feel you've had an hour well spent. It's best watched with only half the mind engaged; that way you won't have to wonder what kind of police force would make space for an amateur historian on the off-chance there would be a few copycat killings from the previous century. Nor will you have to take seriously the possibility that local residents are telling the police: "There's an evil spirit about" when questioned. But watched on auto-pilot, Whitechapel is serviceable enough; Rupert Penry-Jones as the OCD DI Chandler and Phil Davis as the downbeat DS Miles make a decent double-act, and the episode ended with a top-rate locked-cell cliffhanger. If someone bothers to switch the lights on, I'll be back for more next week.

There was more compelling drama in Protecting Our Children (BBC2), a documentary that should be compulsory viewing for those who throw stones at social workers when a Baby P case hits the headlines and moan about the nanny state in the interim. If it was brave of Bristol social services to give access to its caseload, it was braver still of Tiffany and Mike to allow the resulting footage to be shown.

Tiffany and Mike were two of the more hopeless parents you're ever likely to meet. Their two-bedroomed flat was frequently covered in dog excrement and they hadn't even got round to buying a toothbrush or a bed for Toby, their three-year-old son who hadn't yet learned to speak and had behavioural problems. It was left to Suzanne, a social worker on her first case, to try to sort out a mess that seemed to get messier the more social services got involved, as Tiffany and Mike thought everyone was determined to take Toby away from them. It seemed to me as if social services were falling over themselves to find a way for Toby to stay with his parents.

It would be nice to report that after several long chats everyone saw sense, but the resolution was as messy as the flat. Tiffany got pregnant and went into hospital, so social services had to get an interim care order for Toby. When Tiffany went home Mike hit her, so she kicked him out. Months later, she decided to have Toby and her baby adopted. It felt like the right choice for the kids, but God knows what will happen to Tiffany and Mike. Their tragedy looks set to be repeated elsewhere.

If you needed some light relief after that, then Spartacus: Vengeance (Sky1) was ideal, provided your idea of escapism is lashings of video-game sex and violence. Liam McIntyre comes in as the new Spartacus – Andy Whitfield having died of cancer after making the first series – but otherwise it's business as usual with amputations, slow-motion arterial sprays, men with glistening pecs and back, sack and crack waxes, and women with breast surgery sporting Brazilians and accents that vary from American and Australian to cut-glass English. As to what happened, Spartacus was hanging out in an underground chamber near Capua, in between popping out to a brothel to hack a few Romans to death to take vengeance on Glaber. Or something like that. Who really cares? Let's face it, if you're watching for the story then you're missing the point.